Every day we get phone calls asking: "How can I upgrade my 7800 bike without getting the whole 7900 group?" Well, it is a bit tough to wade through all of Shimano's compatibility charts so we figured we would try to help out. The Shimano Dura-Ace 7900 Upgrade kit is the bare minimum needed to get started on your way to a 7900 group on your 7800 bike. Included in the kit are: Dura-Ace ST-7900 STI levers, Dura-Ace FD-7900 Front Derailleur and a Dura-Ace RD-7900 Rear derailleur.
Shimano says that the brakes are completely compatible but you may experience less "rim feel" and that the cranks are compatible but you may experience "slower shifts." Our experience says that this is not any more noticeable than using an aftermarket brake or crank on your current 7800 components. So if you are ready to save weight and eliminate all the cables that are hanging off the front of your bike, here is the way to get started!
We will include a Dura-Ace FD-7900 Braze-on front derailleur as a default, unless you indicate a front derailleur clamp size in the comments section of your online order. There is no up charge for a clamp-on style front derailleur.
For info on 7800-7900 compatibility, see the Shimano Dura-Ace 7900 Compatibility Chart
Great stuff....just keep in mind that the 7800 Flight Deck computer head wont work with the 7900 shifters. Youll need to update to the newer 7900 compatible Flight Deck cyclometer.
I upgraded to the 7900 DuraAce group and what a dream. Shimano still does things right the first time. The shifts are dead on, seamless, and smooth. No chain rub at all. The shifter hoods are super comfy for extended hours in the saddle. I have given up my old Campy Record 10-speed set up for this DuraAce setup and I could not be happier. The 7900 group is as good as it gets and I love the 11-28 cassette for the long climbs. I would suggest that you buy the 7900 DuraAce brakes if you upgrade. My old brake calipers didnt seem to stop me fast enough when I needed to come off high speeds quickly.
The 7900 STI levers may be initially slower out of the box until approx. 1000 miles at which point they are superior to all previous Dura-Ace front derailleurs. Unlike 7700 and 7800, there is no longer a micro-trim click on the big chainring for those looking to trim the front derailleur in extreme cross-chaining.
Properly adjusted, you may notice the micro trim is now on the small chainring (where it should be). This front derailleur is really the first in a while that is truly for racing. Set your chain in the big ring and forget about it. No more rubbing even in extreme chain-crossing.
Break these levers in and Im positive youll find the 7900 D-A carbon levers to be the nicest shifting, most ergonomically comfortable, and lightest STI levers to date. For that matter, so are the new Ultegra STI levers!
Im old enough to have had the pleasure of riding every DA group put out there from AX all the way up to 7900. These levers are worth the money.
7900 shifts considerably slower on the front derailler than my old 7700. My next upgrade from 7700 will be 7800 not 7900 it is Shimanos vista product.
Cant say we agree with this review of 7900 - ed.